1. Field of the Invention
The present invention relates to electronic lock systems and, more specifically, to a combination of an electronic lock system and an environmental control system for controlling the heating and cooling units in a room.
2. Prior Art
Electronic lock systems are commonly employed in hotels, motels, cruise ships and ferries where a room is rented to a guest for a short period of time and there is a need for a high level of security. The electronic lock system, in essence, provides each new guest with a new key and rekeys the lock for each new key used in the lock. Typically, an electronic lock system comprises a key generating station which is located at the check-in counter or front desk of the hotel and an electronic lock which is mounted in a door of a room and provides access to the room. The lock is opened by a key having magnetic data (key code) thereon. Typically, the key is in the form of a card and the magnetic data is encoded onto the key by the key generating station when it is assigned to the guest at the front desk. The lock has a means to read the magnetic data on the key and a microcontroller to compare the key code with an access code. The access code is either generated by the microcontroller through an algorithm or is stored in the memory of the microcontroller. If there is a match between the access code and the key code, then the lock opens and allows access to the room.
In order to insure that the key code and the access code match, the key generating station is either hard wired to the electronic lock so that it can communicate the new key code to the electronic lock; or the key generating station and the microcontroller use the same algorithm to calculate the codes; or the key generating station and the microcontroller store the same codes in their memories.
There are a number of ways that the lock system invalidates a guest key. For instance, the mere use of a new guest key with a new guest key code causes the previously used guest key code to be invalidated. In other cases, the key code includes a start time and an end time or a time period, e.g. a number of hours, during which the guest key code is valid. The use of a time period invalidates the guest key code at the end of the time period, without the need for a new guest key to be inserted in the lock. The use of time thus allows greater control by management of the access to the room by the guests.
Because of the increased security of the electronic lock, most hotels and the like have converted from the conventional metal key locks to the electronic locks.
Environmental control systems are used to control the energy consumption of the various electrical appliances in a room. Typically, hotels employ them to control the heating and cooling unit (HVAC units) of the room. An environmental control system conventionally comprises a motion detector mounted on a wall of the room for detecting when the guest is in the room; a door switch which detects a change in state of the door; e.g. opening and closing of the door; and an energy control unit which is connected to the various electrical appliances of the room. The energy control unit controls the energy consumption of the various electrical appliances in the room, especially the heating, ventilating and air conditioning (HVAC) unit. When the door switch changes state, e.g. the door opens and a guest enters the room, the motion detector is activated to detect the presence of a guest in the room. The motion detector then sends a signal to the energy control unit to set the temperature to some acceptable level. When the guest leaves the room by opening and closing the door, the door switch changes state and the motion detector is activated and detects the absence of the guest. The motion detector then sends a signal to the energy control unit and the energy control unit resets the temperature to allow for a broader temperature range and thus less energy consumption. For instance, in the winter, the guest may set the room temperature at 75.degree. F. (25.degree. C.). However, the hotel management prefers to have the room temperature at 60.degree. F. (15.degree. C.) when the guest is not in the room. The energy control sets the heating unit to the various temperatures depending upon whether the motion detector detects the presence or absence of the guest in the room. The energy control unit can be connected to other electrical appliances other than the HVAC unit. For example, the energy control unit can be connected to the lights, television and radio to insure that these are turned off when the guest leaves the room.
Generally, when a guest has checked into a hotel and has been assigned a room, the room is referred to as being in a sold state. If a room has not been assigned to a guest or if the guest has checked out, then the room is referred to as being in the unsold state.
Furthermore, it should be appreciated that when a room is in the sold state, it can be either in an occupied state, i.e. the guest is present in the room, or in an unoccupied state, i.e. the guest is absent from the room. Generally, the hotel management sets the unsold temperature range at between 85.degree. F. (30.degree. C.) and 50.degree. F. (10.degree. C.) and the sold temperature range at between 75.degree. F. (25.degree. C.) and 60.degree. F. (15.degree. C.). The heating/cooling units are off so long as the room temperature stays within the range. Conventionally, the hotel guest is able to further adjust the temperature range to his specific preference, for example at 70.degree. F. (20.degree. C.) when he occupies the room.
The motion detector communicates with the energy control unit either by wiring of the two units together or by electromagnetic waves (radio or light). Additionally, some environmental control systems as well as some electronic locks are wired to a main terminal which is located at a main desk so that they can be controlled from the main desk.
Using wire to connect the main terminal to the environmental control system and/or the lock is expensive and time-consuming to install. There is a need for a stand-alone lock system that communicates directly with the environmental control system for the room.